Heterogeneous supports for homogeneous catalysts

ABSTRACT

A method of making a heterogenously supported catalyst useful in dimerization, oligomerization or polymerization is provided in which a catalyst precursor containing a metal and an aromatic group are alkylated onto an oligomeric support having at least one terminal unsaturated group by Friedel Crafts alkylation.

PRIOR RELATED APPLICATIONS

The application claims priority to U.S. Application No. 61/362,102,filed Jul. 7, 2010 and incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to methods of supporting catalysts for use indimerization, oligomerization and polymerization reactions.

BACKGROUND OF THE INVENTION

Dimerization of olefins is well known and industrially useful. Inparticular, dimerization of 2-methylpropene to produce2,4,4-trimethylpentene, commonly called isooctane, is a well known anduseful reaction because the product can be used for gasolinereformulation. Branched saturated hydrocarbons, such as isooctane, havea high octane number, low volatility and do not contain sulfur oraromatics, and are, therefore, particularly useful for improvinggasoline and making it more environmentally friendly. Dimerization oflinear olefins also represents an attractive route for the production ofhigh octane number blending components. The branched species, however,may also contribute to engine deposits. Thus, in some instances thelower octane number of products of dimerization of linear olefins may beoffset by lower engine deposits.

Branched saturated hydrocarbons can be produced in different ways, e.g.by alkylation of olefins with isoparaffins and by dimerization of lightolefins, in some instances followed by hydrogenation. Alkylation of2-methylpropene (isobutene) with isobutane directly produces isooctane,and the dimerization reaction of 2-methylpropene produces2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene, amongst otherproducts.

Use of ionic liquids for dimerization and/or oligomerization of olefinsis well known, including for example, the processes disclosed in U.S.Pat. Nos. 5,304,615; 5,731,101; 6,706,936; 6,518,473 and 7,351,780, thedisclosures of which are incorporated herein by reference.

Ionic liquids make an ideal solvent because they have very lowvolatility, and do not evaporate or burn very easily, resulting in saferprocesses. Also, the low melting point and negligible vapor pressurelead to a wide liquid range often exceeding 100 degrees C. (unlike thehundred degree Celsius range limit found for liquid water). Anotheradvantage is that chemical and physical properties of ionic liquids canbe “tuned” by selecting different anion and cation combinations, anddifferent ionic liquids can be mixed together to make binary or ternaryionic liquids. It is even possible to have ionic liquid solvents thatalso function as catalysts or co-catalysts in reactions.

Perhaps the most important benefit of using ionic liquids in variousreactions is simplified separation of the products. Most ionic liquidsare polar, and hence non-polar products—like isooctane and octane—areimmiscible therein. The biphasic process allows separation of theproducts by decantation and reuse of the catalysts. Further, the factthat the product is not miscible in the solvent, also tends to drive thereaction.

It is known that catalysts may be either heterogeneous or homogenouscatalysts.

Homogeneous catalysts act by reacting within a single phase, and thecatalyst is not supported. While a reaction involving a homogenouscatalyst may result in a narrow weight distribution of products, it maybe unfavorable because it can be difficult to separate the product fromthe reactants.

Heterogenous catalysts act by reacting at the boundary of two phases(such as a solid-liquid phase). While heterogeneous catalysts may beless selective than homogenous catalysts, they are advantageous in thatthe products are easier to separate and can offer a continuousmanufacturing process. It would be advantageous therefore, to have acatalyst that provides the separability of a heterogenous catalyst withthe ease of synthesis that can be achieved with ionic liquids.

It would be desirable, therefore, to utilize ionic liquids to attacholigomerization catalysts onto a solid support, thus providing anoligomerization catalyst system and reaction process useful in fixed bedreactors and which is readily used in a refinery environment.

SUMMARY OF THE INVENTION

One aspect of the invention provides a method of making a supportedcatalyst useful in reactions of addition monomers comprising: (a)contacting a catalyst precursor comprising at least one aromatic groupand at least one active catalytic metal with a support materialcomprising at least one terminal unsaturated group in the presence of aLewis acid by Friedel Crafts alkylation to form a supported catalystprecursor; and (b) contacting the supported catalyst precursor with aco-catalyst to form a supported catalyst.

In some embodiments, the support is one or more oligomers. Inalternative embodiments, the support is one or more homo-, inter- orhetero-polymers. In yet other embodiments, the support is a mixture ofoligomers and polymers.

In certain embodiments, the at least one terminal unsaturated group isat least one terminal vinyl group.

In some embodiments of the invention, the at least one active catalyticmetal is selected from the Group 3-10 metals.

In certain embodiments of the inventive method, the support ispolybutadiene having about 10 mol % terminal vinyl groups.

Some embodiments of the invention utilize an ionic liquid as the Lewisacid. In various embodiments, the inventive method employs ionic liquidsconsisting of an organic halide salt, such as an ammonium, phosphonium,or sulfonium salt, and a metal halide salt of aluminium, gallium, boron,iron (III), titanium, zirconium or hafnium.

In some embodiments of the invention, the co-catalyst is one or morealkylaluminum compounds. In particular embodiments, the co-catalyst ismethylaluminoxane, ethylaluminum dichloride, triethylaluminum,diethylaluminum chloride, tri-isobutylaluminum, or a mixture of anythereof.

Another aspect of the invention provides a method for producingsupported catalysts that are useful in dimerization, oligomerization orpolymerization of addition monomers.

Another aspect of the invention provides supported catalysts producedaccording to the inventive method.

Yet another aspect of the invention provides a process for producingdimers from an addition monomer comprising contacting an additionmonomer with the supported catalyst produced according to the inventivemethod.

DESCRIPTION OF THE FIGURES

FIG. 1 illustrates the reaction mechanism for bonding a catalystprecursor onto a support wherein the support is polybutadiene and thecatalyst precursor is diphenylphosphinopropane nickel dichloride to forma supported catalyst precursor.

FIG. 2 illustrates the reaction mechanism of activating the supportedcatalyst precursor with co-catalyst/activator to form an activatedsupported catalyst.

FIG. 3 is a table containing the FID-GC analysis of the product ofExample 1.

FIG. 4 is an NMR trace of the polybutadiene of Example 1 before thealkylation step, showing that the polybutadiene possessed around 10% 1,2linkages.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Embodiments of the invention provide a method of producing a supportedcatalyst precursor for use in dimerization and/or oligomerizationreactions. In some embodiments, the supported catalyst precursor may beactivated, i.e., contacted with one or more activators or co-catalysts,in the presence of an olefin in a dimerization or oligomerizationreactor. In alternative embodiments, the supported catalyst precursormay be activated prior to introduction into a dimerization oroligomerization reactor containing an olefin.

In some embodiments of the invention the catalyst precursor is supportedon a support selected from the group of linear and branched oligomershaving a molecular weight of between 500 and 500,000 and having at leastone terminal unsaturated group, such as a vinyl group.

In alternative embodiments, the support is selected from linear andbranched homo-, inter-, and hetero-polymers wherein the polymer includesat least one terminal unsaturated group.

In some embodiments of the invention, the support is polybutadiene,including e.g., 1,2 and 1,4 polybutadienes.

In preferred embodiments of the invention, the oligomeric or polymericsupport does not include any heteroatoms, such as sulfur, oxygen ornitrogen. In yet other preferred embodiments of the invention, theoligomeric or polymeric support does not include aromatic groups.

Catalyst precursors useful in embodiments of the invention include anyone or more catalyst precursors for use in dimerization oroligomerization reactions and containing one or more metals and one ormore substituted and/or unsubstituted aromatic groups. Whilepolymerization may occur using embodiments of the invention, inpreferred embodiments the catalyst and co-catalyst are optimized for thedimerization reaction.

In specific embodiments, the catalyst precursor is especially useful inolefin dimerization reactions. Examples of such catalyst precursors aredisclosed in U.S. Pat. Nos. 7,223,893, 6,518,473, and 6,291,733, thedisclosures of which are incorporated herein by reference.

In some embodiments of the invention, the co-catalyst (i.e., activator)may be one or more of known such compounds useful in activatingdimerization, oligomerization and/or polymerization catalysts, includingfor example, methylaluminoxane, ethylaluminum dichloride, andtriethylaluminum. Examples of such cocatalysts are disclosed in U.S.Pat. Nos. 7,223,893, 6,518,473, and 6,291,733, the disclosures of whichare incorporated herein by reference.

The catalyst precursor is attached to the support in preferredembodiments by Friedel-Crafts alkylation. Friedel-Crafts reactions arepossible with any carbocationic intermediate such as those derived fromalkenes and a protic acid, Lewis acid, enones, and epoxides.

In alternative embodiments of the invention, the aromatic component of acatalyst precursor may be alkylated onto a heterogenous support. In suchembodiments, the complexation of an active metal may be conducted afterthe alkylation to form a supported catalyst precursor. The supportedcatalyst precursor may then be activated as described herein to form asupported catalyst composition.

Another aspect of the invention provides supported catalysts useful indimerization, oligomerization or polymerization reactions.

As used herein the following terms and abbreviations have the meaningsspecified.

AlC1₃ aluminum trichloride. BMIMCl or C4MIMCl1-butyl-3-methylimidazolium chloride EtAlCl₂ ethylaluminum dichlorideFID Flame Ionization Detector GC Gas Chromatography IL ionic liquidNi(dppe)Cl₂ diphenylphosphine-ethane nickel dichloride Ni(dppp)Cl₂diphenylphosphine-propane nickel dichloride Ni(PPh₃)₂Cl₂bis(triphenylphosphine) nickel dichloride NMR nuclear magnetic resonance

A “catalyst precursor” is a transition metal compound or transitionmetal complex, which when activated by contact with a co-catalyst, isuseful for dimerization, oligomerization or polymerization of additionalpolymerizable monomers.

“IL” or “ionic liquid” as used herein means a Lewis acidic ionic liquidconsisting of an organic halide salt, such as an ammonium, phosphonium,or sulfonium salt, and a metal halide salt of aluminium, gallium, boron,iron (III), titanium, zirconium or hafnium.

The following example is illustrative only and should not serve tounduly limit the scope of the invention.

Example 1

0.38 g of polybutadiene was dissolved in 30 ml methylene chloride atambient atmospheric pressure. The polybutadiene had an approximatemolecular weight of about 110,000 with 89-90 mol % 1,4-linkage and 10-11mol % 1,2-linkage of the butadiene monomers. The term 10-11 mol %1,2-linkage means there are 10-11 mol % pending vinyl groups in thechain, with the remaining double bonds being within the backbone(1,4-linkage).

0.40 g of Ni(dppp)Cl₂ was added to the polybutadiene solution. 1.5 ml ofthe Lewis acidic ionic liquid BMIMCl:AlCl₃ in a 2:1 ratio was slowlyadded to the polybutadiene:Ni(dppp)Cl₂ solution with stirring. Gelationwas observed, indicating the formation of the supported catalystprecursor within several minutes and producing a gel. FIG. 1 illustratesthis reaction in which the catalyst precursor is attached to thepolybutadiene support by Friedel Crafts alkylation.

The gel was transferred into a filtration funnel and washed withacetone. Residual acetone in the gel was removed by high vacuum drying,leaving 0.59 g of powder product, the supported heterogenous catalystprecursor.

EtAlCl₂ in toluene was used as the co-catalyst/activator in thisexample. 30 ml of 1.8 molar EtAlCl₂ in toluene was added to the powderproduct and the mixture was placed in an ultrasonic bath. Thisactivation reaction, in which the supported catalyst is formed bycontact of the supported catalyst precursor with cocatalyst, isillustrated in FIG. 2.

The powder product swelled and the remaining, unabsorbed EtAlCl₂solution was removed by filtration. The swelled powder product,activated heterogenous catalyst, was washed three times with n-pentaneand then stored under n-pentane.

Then the resulting supported catalysts was tested to confirm itscatalytic activity. 6 ml of the activated heterogenous catalystsuspension (which equaled 0.08 g polymer) and 50 ml liquid propene werecombined and placed in an ambient temperature waterbath and stirred for195 minutes. After releasing the pressure, 22.99 g of product remained.Gas Chromatograph (GC) analysis of the product revealed propene dimerand propene trimer content of 76.5 wt % and 17.2 wt %, respectively. SeeFIGS. 3-4. Thus, the novel supported catalyst was functional and highlyselective, resulting in more than 75% dimer formation. Thus, the newcatalyst has high with all of the conveniences of a supported catalyst,especially advantages in recycling the catalyst.

While various embodiments in accordance with the disclosed principleshave been described above, it should be understood that they have beenpresented by way of example only, and are not limiting. Thus, thebreadth and scope of the invention(s) should not be limited by any ofthe above-described exemplary embodiments, but should be defined only inaccordance with the claims and their equivalents issuing from thisdisclosure. Furthermore, the above advantages and features are providedin described embodiments, but shall not limit the application of suchissued claims to processes and structures accomplishing any or all ofthe above advantages.

The following patents are incorporated by reference herein in theirentirety.

-   U.S. Pat. No. 5,304,615-   U.S. Pat. No. 5,731,101-   U.S. Pat. No. 6,291,733-   U.S. Pat. No. 6,518,473-   U.S. Pat. No. 6,518,473-   U.S. Pat. No. 6,706,936-   U.S. Pat. No. 7,223,893-   U.S. Pat. No. 7,351,780

1. A method of making a supported catalyst comprising: (a) contacting acatalyst precursor comprising at least one aromatic group and at leastone active catalytic metal with a support material comprising at leastone terminal unsaturated group in the presence of a Lewis acid byFriedel Crafts alkylation to form a supported catalyst precursor; (b)contacting the supported catalyst precursor with a co-catalyst to form asupported catalyst.
 2. The method of claim 1 wherein the supportmaterial is one or more oligomers.
 3. The method of claim 1 wherein thesupport material is one or more homo-, inter- or hetero-polymers.
 4. Themethod of claim 1 wherein the at least one terminal unsaturated group isat least one terminal vinyl group.
 5. The method of claim 1 wherein thesupported catalyst is useful in dimerization, oligomerization orpolymerization of addition monomers.
 6. The method of claim 1 whereinthe at least one active catalytic metal is selected from the Group 3-10metals.
 7. The method of claim 1 wherein the support is polybutadienehaving about 10 mol % terminal vinyl groups.
 8. The process of claim 1wherein the co-catalyst is one or more alkylaluminum compounds.
 9. Theprocess of claim 1 wherein the co-catalyst is methylaluminoxane,ethylaluminum dichloride, triethylaluminum, diethylaluminum chloride,tri-isobutylaluminum, or a mixture of any thereof.
 10. The process ofclaim 1 wherein the co-catalyst is ethylaluminum dichloride.
 11. Thesupported catalyst produced according to the process of claim
 1. 12. Thesupported catalyst produced according to the process of claim
 2. 13. Thesupported catalyst produced according to the process of claim
 3. 14. Thesupported catalyst produced according to the process of claim
 4. 15. Thesupported catalyst produced according to the process of claim
 5. 16. Thesupported catalyst produced according to the process of claim
 6. 17. Thesupported catalyst produced according to the process of claim
 7. 18. Thesupported catalyst produced according to the process of claim
 8. 19. Thesupported catalyst produced according to the process of claim
 10. 20. Aprocess for producing dimers from an addition monomer comprisingcontacting an addition monomer with the supported catalyst producedaccording to the process of any of claims 1-10.
 21. A method of making asupported catalyst comprising: (a) contacting a catalyst precursorcomprising at least one aromatic group and at least one active catalyticmetal with a support material comprising at least one terminalunsaturated group in the presence of a Lewis acid ionic liquid byFriedel Crafts alkylation to form a supported catalyst precursor; (b)contacting the supported catalyst precursor with a co-catalyst to form asupported catalyst.